(a) Field of the Invention
The present invention relates to plastic floorings using concave portions and convex portions, specifically to an assembly structure of the plastic floorings absorbing heat expansions as well as forming a space area between the concave portions and the convex portions to minimize the deformation of the plastic floorings so that alien substances of a floor surface does not protrude up to the surface of the floorings.
(b) Related Arts
Plastic floorings used for installing floors of a building are individually manufactured so that they have a surface area of a certain standard. The plastic floorings are used with other types of plastic floorings to constitute the floors of the building. Typical plastic floorings mostly have a form of a square shape having perpendicular corners and a certain thickness. At the side surfaces of each flooring, unique assembly structures are implemented which allow them to be assemble with other types of floorings.
FIG. 8 is a cross section view of plastic floorings according to a prior art in which each plastic floorings (1) has steps in a form of stairs connected to other plastic floorings (1′) so that multiple floorings (1, 1′) are assembled in a continuous overlapping manner.
Above assembly structures, however, have the shortcomings of having a height difference between the floorings when the floor to which the floorings are installed is bumpy because the floorings do not closely and firmly adjoin each other in the area connecting the floorings.
Therefore, plastic floorings (3) having concave portions (5) and convex portions (7) on the side surfaces of each flooring (3) as illustrated in FIG. 9 have been proposed to closely adjoin the connecting areas of the floorings.
That is, the plastic flooring (3) has the convex portion (7) at the left side of the drawing and concave portion (5) at the right side of the drawing. The assembly of the floorings (3, 3′) is enabled by inserting the convex portion (7) into the concave portion (5) of the other plastic floorings (3′) and engaging the concave portion (5) with the convex portion (7) of the other plastic floorings (3′).
In floorings (3) with such a structure, however, the concave portions (5) and the convex portions (7) engage in a close manner so that when the heat from the bottom surface is transferred to the plastic flooring, each plastic flooring expands toward the other plastic flooring adjacent to it. As a result, distortion in the connection portion of the flooring (3) occurs as can seen in FIG. 10, which seriously degrades the quality of the floorings.
Furthermore, many alien substances such as adhesives exist on the bottom floor (9) to which the floorings (3) are installed. After the installation, the alien substances (3) protrude beyond the connection portions, exposing itself out on the surface of the floorings. These alien substances weaken the adjoining force between the concave portion (5) and the convex portion (7), which causes the problem of deteriorating adjoining force among the floorings.